1. 1
Given the following:
Find . Where both angles are in the fourth quadrant.

2. 2
First we need to find and
We know that we are given
So we need to solve for the hypotenuse side.

3. 3
Now that we have the hypotenuse
side, we now know that:

4. 4
Now we need to find and
We know that we are given
So we just need to solve for the hypotenuse.

5. 5
After knowing what the hypotenuse side is ,
we can now safely say that:

6. 6
But before we substitute the values there is a
minor thing that we need to consider. It says
that both alpha and beta are in the fourth
quadrant , which means that both values of
sine will be negative.

7. 7
Now we have all we need. We can just substitute it
in the formula.

8. 8
Do some arithmetic then you will get the
same answer.